High power radiofrequency amplifiers, such as Doherty amplifiers as well as single-ended class AB amplifiers, tend to exhibit memory effects. Memory effects are particularly problematic at frequencies of 1 GHz and above. These memory effects result from parasitic inductances between the power supply and the amplifier and from the speed of variation and magnitude of current consumption by the amplifier, which follows the envelope of the input signal modulation. Such parasitic inductances may exist as part of a power supply network. At higher modulation frequencies larger distortions tend to appear due to such memory effects. Doherty amplifiers tend to exhibit higher memory effects due to operation of the peak amplifier in C-class mode.
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